Integrated circuits can be damaged by high voltage spikes produced by electrostatic discharge (ESD). High static charges can develop on objects such as a human body. Consider a situation in which a packaged integrated circuit is free and is not coupled to a printed circuit. Power and ground conductors within the integrated circuit may be resting at a first potential. If a person were charged with a static charge, and then were to touch a terminal of the integrated circuit, the high static voltage charge on body of the person might be discharged quickly through the terminal and into the integrated circuit until the integrated circuit and the human body equalize at a common potential. Such an electrostatic discharge event may momentarily introduce high local voltages and high currents into the integrated circuit. These momentary high voltages and currents may permanently damage the integrated circuit. Damage from an ESD event may occur both during integrated circuit manufacture or may occur later during use of an electronic consumer device that incorporates the integrated circuit.
To prevent ESD events from damaging integrated circuits, circuits called electrostatic discharge (ESD) protection devices are commonly incorporated into integrated circuits. An ESD protection circuit has circuitry that is able to shunt the momentary high currents of an ESD discharge event, thereby preventing a high voltage from developing across a transistor or other easily damaged component of the integrated circuit. One type of integrated circuit that should be protected from ESD event damage is an integrated circuit that involves a sensitive analog amplifier circuit referred to as a Low Noise Amplifier (LNA). This type of integrated circuit involving an LNA is typically found in cellular telephones. In the LNA, the gate of a field effect transistor is typically coupled directly or through a capacitor to bond pad or microbump of the integrated circuit. This bond pad or microbump is coupled to circuitry outside the integrated circuit via an integrated circuit package that houses the integrated circuit. ESD protection circuits have worked well in protecting the gate of this field effect transistor in the past, but more recently as the size of the integrated circuits that include such LNA circuits has increased, the input field effect transistors of LNA circuits have been seen to fail due to ESD damage. An improved LNA input circuit is desired.